Methods of selectively recovering palladium from a palladium-containing material

Patent metadata

Field	Value
Publication number	US-2021047708-A1
Application number	US-201916541930-A
Country	US
Kind code	A1
Filing date	Aug 15, 2019
Priority date	Aug 15, 2019
Publication date	Feb 18, 2021
Grant date	—

Abstract

A method of selectively recovering palladium from a palladium-containing material comprises providing a leaching solution comprising hydrochloric acid, hydrogen peroxide, and an iron salt comprising one or both of ferric chloride or ferrous chloride and contacting a palladium-containing material with the leaching solution to dissolve palladium from the palladium-containing material. Related methods of selectively recovering palladium from a palladium-containing material are also disclosed.

First claim

What is claimed is:

1 . A method of selectively recovering palladium from a palladium-containing material, the method comprising:
providing a leaching solution comprising hydrochloric acid, hydrogen peroxide, and an iron salt comprising one or both of ferric chloride or ferrous chloride; and contacting a palladium-containing material with the leaching solution to dissolve palladium from the palladium-containing material.

2 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution having a ratio of iron to hydrogen peroxide within a range from about 1.0:50.0 to about 1.0:250.

3 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution comprising the iron salt within a range from about 1.0 mM to about 20.0 mM.

4 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution comprising:
between about 0.01 M and about 10.0 M hydrochloric acid; between about 0.1 weight percent to about 30.0 weight percent hydrogen peroxide; and between about 1.0 mM and about 20.0 mM of the iron salt.

5 . The method of claim 1 , wherein contacting a palladium-containing material with the leaching solution comprises contacting a catalytic converter with the leaching solution.

6 . The method of claim 1 , further comprising contacting the dissolved palladium with one or more of zinc, aluminum, or tin to precipitate palladium from the solution.

7 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution comprising about 1.0 part ferric ions for between about 100 and about 200 parts hydrochloric acid.

8 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution comprising ferric ions within a range of from about 5.0 mM to about 50 mM for every about 1.0 M of hydrochloric acid.

9 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution from about 50.0 to about 250 parts by weight hydrogen peroxide for every about 1.0 part by weight of ferric ions.

10 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution at a temperature within a range from about 15° C. to about 80° C.

11 . The method of claim 1 , wherein providing a leaching solution comprises providing a leaching solution at a temperature within a range from about 18° C. to about 25° C.

12 . A method of recovering palladium from a palladium-containing material, the method comprising:
providing, to a palladium leaching vessel, a leaching solution comprising an acid, an oxidizer, and ferric ions; and contacting a palladium-containing material with the leaching solution to selectively dissolve palladium from the palladium-containing material and form a solution comprising dissolved palladium.

13 . The method of claim 12 , wherein contacting a palladium-containing material with the leaching solution to selectively dissolve palladium from the palladium-containing material comprises dissolving palladium from the palladium-containing material without substantially dissolving platinum from the palladium-containing material.

14 . The method of claim 12 , further comprising contacting the solution comprising dissolved palladium with a palladium leaching agent selected from the group consisting of zinc, tin, and aluminum to form a substantially palladium-free solution.

15 . The method of claim 12 , further comprising recycling at least a portion of the substantially palladium-free solution to the palladium leaching vessel.

16 . The method of claim 12 , wherein providing, to a palladium leaching vessel, a leaching solution comprises providing a leaching solution to the palladium leaching vessel at a temperature less than about 25° C.

17 . The method of claim 12 , wherein providing, to a palladium leaching vessel, a leaching solution comprising an acid, an oxidizer, and ferric ions comprises providing a leaching solution comprising less ferric ions by weight than the oxidizer by weight to the palladium leaching vessel.

18 . The method of claim 12 , wherein providing a leaching solution comprising an acid, an oxidizer, and ferric ions comprises providing a leaching solution comprising between about 80 parts and about 90 parts by weight of hydrogen peroxide for every about 1.0 part by weight ferric ions or ferrous ions.

19 . The method of claim 12 , wherein providing a leaching solution comprising an acid, an oxidizer, and ferric ions comprises providing a leaching solution comprising one or more of ferric chloride, ferrous chloride, iron bromide, iron fluoride, ferrous iodide, iron molybdate, iron oxalate dihydrate, iron perchlorate hydrate, iron sulfate hydrate, or iron sulfate.

20 . A method of selectively recovering palladium from a palladium-containing material, the method comprising:
contacting, at a temperature less than about 25° , a palladium-containing material with a leaching solution to form a solution comprising dissolved palladium, the leaching solution comprising:
from about 1.0 M to about 2.0 M hydrochloric acid;
from about 1.0 weight percent to about 10.0 weight percent hydrogen peroxide; and
from about 5 mM ferrous chloride to about 10 mM ferrous chloride; and
removing the dissolved palladium from the solution comprising dissolved palladium.

Assignees

• Battelle Energy Alliance Llc

Inventors

• Lister Tedd E
• Diaz Aldana Luis A

Classifications

• Y02P10/20

  Recycling · CPC title

• C22B11/046 Primary

  from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths · CPC title

• C22B3/44

  by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42) · CPC title

• C22B3/46

  by substitution, e.g. by cementation · CPC title

• C22B11/048

  from spent catalysts · CPC title